Sliding device for drawer

ABSTRACT

Disclosed herein is a sliding device for guiding a drawer such that the drawer is extended from or retracted into a storage body. The sliding device includes sliding rails each having a pair of flanges, and balls slidably connecting the sliding rails to each other. Each flange includes a raceway in which a portion of the corresponding ball is disposed. The raceway guides the ball such that the ball rolls in a direction of extension or retraction of the drawer. The raceway includes a bent part and support surfaces. The bent part extends parallel to the direction of extension or retraction of the drawer. The bent part is concave in a direction in which the ball is inserted into the raceway. The support surfaces are disposed forming a symmetric structure with respect to an imaginary line connecting a center point of the ball to the bent part.

TECHNICAL FIELD

The present invention generally relates to sliding devices for drawers and, more particularly, to a sliding device that is installed in an electronic apparatus or furniture provided with a drawer for storing an object therein so as to guide extension or retraction of the drawer.

BACKGROUND ART

Generally, drawers are widely used in a variety of storage means, for example, furniture and electronic apparatuses such as refrigerators, so as to store objects. Such a drawer is provided with a sliding device so that the drawer can be easily opened or closed.

FIG. 1 illustrates a storage means provided with typical sliding devices for a drawer. FIG. 2 is a sectional view of the storage means of FIG. 1.

Referring to FIGS. 1 and 2, the storage means 10 for storing objects (not shown) includes a storage body 11 having a storage space 12 therein, and a drawer 13. Sliding devices 100 and 100′ respectively connect opposite sides of the drawer 13 to the storage body 11.

The drawer 13 for storing objects (not shown) therein is guided by the sliding devices 100 and 100′ such that the drawer 13 slides relative to the storage body 11 in a direction parallel to the X-axis of coordinates of FIG. 1 and thus is extended from the storage space 12 in a direction designated by reference character A or retracted into the storage space 12 in a direction designated by reference character B.

For reference, the sliding device 100 disposed at a first side of the drawer 13 is symmetrical to the sliding device 100′ disposed at a second side of the drawer 13 with reference to the drawer 13. Given this, only the sliding device 100 is illustrated in FIG. 1.

FIG. 3 is an enlarged sectional view of the sliding device illustrated in FIG. 2.

The sliding device 100 includes a plurality of sliding rails 110, 130, and 150 and balls 120, 120′, 140, and 140′. Each sliding rail 110, 130, 150 respectively has on opposite edges thereof a pair of flanges 111 and 111′, 131 and 131′, 151 and 151′ that are symmetrical to each other with respect to a longitudinal central line (not shown) parallel to the X-axis of coordinates of FIG. 1. The longitudinal central line that is not shown in FIG. 1 will be explained later herein with reference to FIG. 4.

Each ball 120, 120′, 140, 140′ is disposed between the corresponding adjacent two of the flanges 111, 111′, 131, 131′, 151, and 151′. The balls 120, 120′, 140, and 140′ slidably connect the sliding rails 110, 130, and 150 to each other. Guiding the movement of the balls 120 and 140, raceways 113, 133, 135, and 153 are formed in the flanges 111, 131, and 151. Raceways for guiding the movement of the balls 120′ and 140′ are also formed in the flanges 111′, 131′, and 151′ although the reference numerals of these raceways have been omitted.

The construction and operation of the sliding device 100 were described in detail in Korean Patent Unexamined Publication No. 10-2008-0059697, filed by the applicant of the present invention; therefore, further explanation thereof will be omitted. The sliding device 100′ has a symmetric structure with respect to the sliding device 100, and explanation thereof is thus deemed unnecessary.

A load G including the weight of the drawer 12 and the weight of objects received therein is applied to the drawer 12. Furthermore, as shown in the drawing, when the drawer 13 is opened, force F derived from the load G or external force is applied to the outer end of the drawer 13 downward in the vertical direction, that is, in a direction parallel to the Z-axis of coordinates of FIG. 1. Reaction force F′ to the force F is applied to the inner end of the drawer 13 upward in the vertical direction parallel to the Z-axis.

Torsional loads M and M′ are respectively applied to the sliding devices 100 and 100′ by the forces G, F, and F′.

As shown by the curved arrows of FIG. 2, the torsional load M is applied to the sliding device 100, disposed at the first side of the drawer 13, in the clockwise direction with respect to the longitudinal central line. The torsional load M is applied to the sliding device 100′, disposed at the second side of the drawer 13, in the counterclockwise direction.

For reference, detailed explanation of the torsional load applied to the sliding device 100 is in Korean Patent Registration No. 10-1021574, filed by the applicant of the present invention. Therefore, further explanation of the torsional load will be omitted.

Because of the torsional loads M applied to the sliding device 100, forces P1 and P2 are applied to the ball 120 between the flanges 111 and 131 in a direction inclined by a predetermined angle θ relative to the vertical direction VL, that is, relative to the direction parallel to the Z-axis. The forces P1 and P2 acting in a direction inclined by a predetermined angle θ are applied in the opposite directions to each other.

Such forces P1 and P2 acting in a direction inclined by a predetermined angle θ are also applied between the other balls 120′, 140, and 140′ and the flanges 131, 151, 111′, 131′, and 151′ of the sliding device 100 in a direction inclined by a predetermined angle θ relative to the vertical direction VL. Furthermore, forces acting in a direction inclined relative to the vertical direction are also applied by the torsional load M′ to the sliding device 100′ disposed on the second side of the drawer 13; however, illustration of these forces is deemed unnecessary for the sake of explanation.

Typically, each raceway 113, 133, 135, 153 has a shape that can support force applied parallel to the vertical direction VL. Therefore, when forces P1 and P2 acting in a direction inclined relative to the vertical direction VL are applied to the corresponding balls 120, 120′, 140, and 140′, the balls 120, 120′, 140, and 140′ may move along abnormal trajectories by the forces P1 and P2, rather than moving along the original trajectories parallel to the direction of the movement of the drawer 13, while the drawer 13 is repeatedly extended in the direction B or retracted in the direction A. If the balls 120 or 140 are frequently displaced from the original trajectory, the shape of the raceway 113, 133, 135, or 153 may be gradually deformed or abnormally worn.

If the sliding rail 110, 130, or 150 is deformed or abnormally worn because of the above reasons, the drawer 13 may not be smoothly opened or closed, or noise may occur during the extension or retraction process of the drawer 13. In addition, the lifetime of the sliding rail 110, 130, or 150 may be reduced.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to prevent a sliding device for a drawer from being deformed or abnormally worn and to increase the lifetime of the sliding device.

Technical Solution

In order to accomplish the above object, the present invention provides a sliding device for guiding a drawer such that the drawer is extended from or retracted into a storage space formed in a storage body. The sliding device includes: a plurality of sliding rails each having a pair of flanges; and a plurality of balls slidably connecting the sliding rails to each other. Each of the flanges may include a raceway in which a portion of the corresponding ball is disposed. The raceway guides the ball such that the ball rolls in a direction of extension or retraction of the drawer. The raceway includes: a bent part extending parallel to the direction of extension or retraction of the drawer, the bent part being concave in a direction in which the ball is inserted into the raceway; and a plurality of support surfaces disposed forming a symmetric structure with respect to an imaginary line connecting a center point of the ball to the bent part, the support surfaces supporting the ball thereon.

The support surfaces may comprise a pair of support surfaces.

Each of the pair of support surfaces may have a planar shape.

Each of the pair of support surfaces may have a curved shape that is concave toward a portion thereof making contact with the ball. A radius of curvature of the support surface may range from more than 50% of a diameter of the ball to 60% of the diameter of the ball.

Each of the pair of support surfaces may have therein a support depression in which a portion of the ball is disposed. The support depression may extend parallel to the direction of extension or retraction of the drawer. A radius of curvature of the support depression may range from 50% of a diameter of the ball to 60% of the diameter of the ball. The support depression may have a radius of curvature corresponding to a radius of the ball so that the support depression comes into line contact with the ball.

A space may be defined between the bent part and the corresponding ball.

Advantageous Effects

In embodiments of a sliding device for a drawer according to the present invention, a support surface that can support force applied to balls in a direction inclined to the vertical direction is formed on a raceway. Thereby, the sliding rail can be prevented from being deformed or abnormally worn, and the lifetime of the sliding device can be increased.

Furthermore, a space is formed between the raceway and the balls so that a lubricant is retained in the space or fine dust caused by abrasion between parts is collected. Thereby, even after the sliding device has been used over a long period of time, the sliding device can be reliably operated.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a storage means provided with typical sliding devices for a drawer;

FIG. 2 is a sectional view of the storage means of FIG. 1;

FIG. 3 is a sectional view of the sliding device illustrated in FIG. 2;

FIG. 4 is a sectional view illustrating a sliding device for a drawer according to a first embodiment of the present invention;

FIG. 5 is an enlarged view of portion V of FIG. 4; FIG. 6 is a sectional view illustrating a sliding device for a drawer according to a second embodiment of the present invention; FIG. 7 is an enlarged view of portion VII of FIG. 6;

FIG. 8 is a sectional view illustrating a sliding device for a drawer according to a third embodiment of the present invention; and

FIG. 9 is an enlarged view of portion IX of FIG. 8.

BEST MODE

The present invention will now be described in detail based on aspects (or embodiments). The present invention may, however, be embodied in many different forms and should not be construed as being limited to only the embodiments set forth herein, but should be construed as covering modifications, equivalents or alternatives falling within ideas and technical scope of the present invention. In the following description of the invention, if the related known functions or specific instructions on configuring the gist of the present invention unnecessarily obscure the gist of the invention, the detailed description thereof will be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

FIG. 4 is a sectional view illustrating a sliding device for a drawer according to a first embodiment of the present invention.

Referring to FIG. 4, a sliding device 200 for a drawer according to a first embodiment of the present invention includes three sliding rails 210, 230, and 250, and a plurality of balls 220 and 240. The sliding device 200 may further include a retainer that supports the balls 220 and 240 to maintain a constant distance between the balls 220 and 240. However, illustration of the retainer is omitted for the sake of explanation.

Each sliding rail 210, 230, 250 includes a pair of flanges 211, 231, 251.

For the sake of explanation, the three sliding rails 210, 230, and 250 respectively refer to the first sliding rail 210, the second sliding rail 230 and the third sliding rail 250 according to a sequence of arrangement.

Two flanges 211 and 211′ are provided on the first sliding rail 210 to be symmetric with respect to a longitudinal central line CL1. Two flanges 231 and 231′ are provided on the second sliding rail 230 to be symmetrical with respect to a longitudinal central line CL2. Two flanges 251 and 251′ are provided on the third sliding rail 250 to be symmetrical with respect to a longitudinal central line CL3.

Balls 220 and 220′ are respectively provided in spaces between the flanges 211 and 211′ of the first sliding rail 210 and the flanges 231 and 231′ of the second sliding rail 230 that are disposed adjacent to the flanges 211 and 211′. Balls 240 and 240′ are respectively provided in spaces between the flanges 231 and 231′ of the second sliding rail 230 and the flanges 251 and 251′ of the third sliding rail 250 that are disposed adjacent to the flanges 231 and 231′.

A raceway 213 in which a portion of the ball 220 is disposed is formed in a surface of the flange 211 of the first sliding rail 210. A raceway 233 in which a portion of the ball 220 is disposed is also formed in a first surface of the flange 231 of the second sliding rail 230 that faces the ball 220.

A raceway 235 in which a portion of the ball 240 is disposed is formed in a second surface of the flange 231 of the second sliding rail 230 that faces the ball 240. A raceway 253 in which a portion of the ball 240 is disposed is formed in a surface of the flange 251 of the third sliding rail 250 that faces the ball 240.

Although it is not shown in the drawings, a plurality of balls 220 and a plurality of balls 240 are arranged in the longitudinal direction of the sliding rails 210, 230, and 250, that is, in the direction parallel to the X-axis indicated in the drawings or to the longitudinal central lines CL1, CL2, and CL3. Each raceway 213, 233, 235, 253 is formed in a direction (B of FIG. 1) in which a drawer (13 of FIG. 1) is retracted or in a direction (A of FIG. 1) in which the drawer is extended, that is, in the direction parallel to the X-axis. The balls 220 and 240 are guided by the corresponding raceways 213, 233, 235, and 253 such that the drawer can slide in the retraction direction B or the extension direction A.

Furthermore, raceways are also respectively formed in the flanges 211′, 231′ and 251′, although they are not designated by reference numerals. The balls 220′ and 240′ are partially disposed in the respective raceways. Thus, the balls 220′ and 240′ can roll in the direction parallel to the retraction direction B or extension direction A of the drawer 13 under guidance of the raceways.

Therefore, the first sliding rail 210 and the second sliding rail 230 are coupled to each other so as to be slidable relative to each other by the balls 220 and 220′ in the direction parallel to the X-axis of coordinates. The second sliding rail 230 and the third sliding rail 240 are coupled to each other so as to be slidable relative to each other by the balls 240 and 240′ in the direction parallel to the X-axis of coordinates.

That is, of the sliding rails 210, 230, and 250, the adjacent sliding rails are coupled to each other so as to be slidable in the direction parallel to the retraction direction B or the extension direction A of the drawer 13.

To make the sliding rails 210, 230, and 250 smoothly slide relative to each other, as shown in the drawings, the sliding rails 210, 230, 250 are oriented such that all of the longitudinal central lines CL1, CL2, and CL3 are parallel to the X-axis of coordinates.

For reference, the second sliding rail 230 is provided to increase the distance range within which the sliding device 200 can guide the retraction B and the extension A of the drawer 13. Although it is not shown in the drawings, as needed, at least one additional sliding rail (not shown) and a plurality of additional balls (not shown) may be provided between the second sliding rail 230 and the third sliding rail 250.

Alternatively, although it is not shown in the drawings, if the sliding device 200 is used in a small drawer 13 and thus does not require a comparatively long distance range within which the drawer 13 can be extended, the first sliding rail 210 and the third sliding rail 250 may be directly coupled to each other. In this case, the second sliding rail 230 and the balls 220 or 240 are not provided, and the distance between the flanges 211 of the first sliding rail 210 is reduced, or the distance between the flanges 251 of the third sliding rail 250 is increased.

In other words, the sliding device 200 according to the first embodiment of the present invention may have a three stage structure having the three sliding rails 210, 230, and 250. Alternatively, the sliding device 200 may be used as one of sliding devices having other multiple stage structures, for example, a two stage structure or more than three stage structure.

This can be applied to other embodiments of the present invention, which will be explained later herein.

FIG. 5 is an enlarged view of portion V of FIG. 4.

Referring to FIG. 5, a pair of support surfaces 2131 and 2133 and a bent part 2135 are formed in the raceway 213 formed in each flange 211 of the first sliding rail 210. For the sake of explanation, the support surfaces 2131 and 2133 respectively refer to a first support surface 2131 and a second support surface 2133.

The bent part 2135 is concave in a direction in which the ball 220 is inserted into the raceway 213, so that a portion of the ball 220 can be disposed in the raceway 213. The bent part 2135 is formed parallel to the retraction direction (B of FIG. 1) or the extension direction (A of FIG. 1) of the drawer (13 of FIG. 1).

That is, the first support surface 2131 and the second support surface 2133 are formed on opposite sides of the bent part 2135 so as to form a concave bent shape. A portion of a first side of the ball 220 is disposed in the concave bent part. The ball 220, of which a portion of the first side is disposed in the raceway 213, is brought into contact with and supported by the first support surface 2131 and the second support surface 2133.

The first support surface 2131 and the second support surface 2133 are symmetrical to each other with respect to an imaginary line IC1 connecting the bent part 2135 to a center point O1 of the ball 220. An angle θ1 between the imaginary line IC1 and the first support surface 2131 is the same as an angle θ2 between the imaginary line IC1 and the second support surface 2133.

Meanwhile, a pair of planar support surfaces 2331 and 2333 and the bent parts 2335 are also formed in the raceway 233 formed in the first surface of the flange 231 of the second sliding rail 230. For the sake of explanation, the support surfaces 2331 and 2333 respectively refer to a third support surface 2331 and a fourth support surface 2333.

The bent part 2335 is concave in a direction in which the ball 220 is inserted into the raceway 233, so that a portion of the ball 220 can be disposed in the raceway 233. The bent part 2335 is also formed parallel to the retraction direction B or the extension direction A of the drawer 13.

That is, the third support surface 2331 and the fourth support surface 2333 are formed on opposite sides of the bent part 2135 so as to form a concave bent shape. A portion of a second side of the ball 220 is disposed in this concave bent part. The ball 220, of which a portion of the second side is disposed in the raceway 233, is brought into contact with and supported by the third support surface 2331 and the fourth support surface 2333.

The third support surface 2331 and the fourth support surface 2333 are symmetrical to each other with respect to an imaginary line IC2 connecting the bent part 2335 to the center point O1 of the ball 220. An angle θ3 between the imaginary line IC2 and the third support surface 2331 is the same as an angle θ4 between the imaginary line IC2 and the fourth support surface 2333.

A contact point between the ball 220 and the first support surface 2131 refers to a first support point 2132. A contact point between the ball 220 and the second support surface 2133 refers to a second support point 2134. A contact point between the ball 220 and the third support surface 2331 refers to a third support point 2332. A contact point between the ball 220 and the fourth support surface 2333 refers to a fourth support point 2334. In this case, the ball 220 is surrounded by the four support surfaces 2131, 2133, 2331, and 2333 and is brought into contact with and supported by the four support points 2132, 2133, 2332, and 2334.

That is, the raceways 213 and 233 that form a shape surrounding the ball 220 use the four support surfaces 2131, 2133, 2331, and 2333 to support the ball 220. Therefore, the raceways 213 and 233 have the four support points 2132, 2133, 2332, and 2334, the number being twice that of the conventional sliding device (100 of FIG. 1). Consequently, a load applied to the sliding device 100 according to the first embodiment of the present invention is uniformly dispersed, whereby the load support performance of the sliding device 100 can be enhanced, and the expected lifetime thereof can be increased.

Because the sliding device 200 according to the first embodiment of the present invention has the above-mentioned construction, the balls 220 can be guided by the raceways 213 and 233 such that the balls 220 roll in the direction parallel to the retraction direction B or extension direction A of the drawer 13. In addition, even when force is applied to the balls 220 in a direction (refer to P1 or P2 of FIG. 1) inclined to a vertical direction (VL of FIG. 3), the balls 220 can be prevented from being displaced from the original trajectory while rolling along the raceways 213 and 233.

Therefore, in the sliding device 200 according to the first embodiment of the present invention, the sliding rails 210 and 230 can be prevented from being undesirably deformed or worn, and noise can be prevented. The lifetime of the sliding device 200 can also be increased.

Meanwhile, a space 2136 is defined between the bent part 2135 formed the raceway 213 of the first sliding rail 210 and an outer circumferential surface of the first side of the ball 220. A space 2336 is defined between the bent part 2335 formed the raceway 233 of the second sliding rail 230 and an outer circumferential surface of the second side of the ball 220.

Although it is not shown in the drawings, a lubricant is applied between the balls 220 and the raceways 213 and 233 to make the rolling of the balls 220 easier. Here, as the rolling of the balls 220 is repeated, oil films that have been formed between the support points 2132, 2133, 2332, and 2334 and the outer circumferential surfaces of the balls 220 may be become lost. However, in the sliding device 200 according to the first embodiment the present invention, the lubricant that has been present in the spaces 2136 and 2336 moves to the support points 2132, 2133, 2332, and 2334 and the outer circumferential surfaces of the balls 220, thus replenishing the oil films so that the lubricant effect can be sustained.

Furthermore, as contact between the balls 220 and the four support surfaces 2131, 2133, 2331, and 2333 continues, fine dust may be caused by abrasion therebetween. Such fine dust impedes the rolling of the balls 220. However, in the sliding device 200 according to the first embodiment the present invention, such fine dust can be collected in the spaces 2136 and 2336. Therefore, even after the sliding device 200 is used over a long period of time, the balls 220 can smoothly roll.

Meanwhile, the above-stated two imaginary lines IC1 and IC2 may be formed parallel to the vertical direction VL. In this case, an angle (e5, refer to FIG. 5) between the two imaginary lines IC1 and IC2 is 180°, and the angles θ1, θ2, θ3, and θ4 of the four support surfaces 2131, 2133, 2331, and 2333 relative to the vertical direction VL are the same as each other.

For reference, if the four support surfaces 2131, 2133, 2331, and 2333 are oriented perpendicular to the direction of the force (refer to P1 or P2) that is applied toward the center point O1 of the ball 220 in a direction inclined to the vertical direction (VL of FIG. 3), the four support surfaces 2131, 2133, 2331, and 2333 can most effectively support the force P1 or P2.

The orientation angles of the four support surfaces 2131, 2133, 2331, and 2333 that aim to the above purpose may be calculated by simulations or the like. Alternatively, the orientation angles may be determined in such a way that an actual sliding device 200 is manufactured and installed in the storage means (refer to 10 of FIG. 1) and then a test is conducted.

Meanwhile, the raceway 235 is formed on the second surface of the flange 231 of the second sliding rail 230. A pair of support surfaces 2351 and 2353, and a bent part 2355 are formed in the raceway 235.

The bent part 2355 is concave in a direction in which the ball 240 is inserted into the raceway 235, so that a portion of the ball 240 can be disposed in the raceway 235. The bent part 2355 is formed parallel to the retraction direction B or the extension direction A of the drawer 13.

The balls 220 and 240 are respectively disposed on the opposite sides of the flange 231 of the second sliding rail 230. Given this, the structures of the raceways 235 and 253 that guide the ball 240 rolling in the direction parallel to the retraction direction B or the extension direction A of the drawer 13 are respectively the same as those of the above-mentioned raceways 213 and 233, except that the raceways 213 and 233 are related to the first sliding rail 210 while the raceways 235 and 253 are related to the third sliding rail 250. Therefore, further explanation will be omitted.

Generally, two sliding devices 200 are symmetrically installed on the respective opposite sides of the drawer (13 of FIG. 1). Therefore, if the sliding device 200 is configured such that it can be used on either side of the drawer 13, the compatibility of the sliding device 200 as well as parts constituting the sliding device 200 can be enhanced, and inventory can be reduced.

To make is possible to use the sliding device 200 on either side of the drawer 13, for example, the sliding device 200 must be configured such that the sliding device installed on one side of the drawer 13 and the sliding device installed on the other side of the drawer 13 are symmetric with respect to the drawer 13.

To achieve the above purpose, for instance, the sliding device 200 has a symmetric structure with respect to a central plane CS. The term “central plane” refers to a plane on which all of the longitudinal central lines CL1, CL2, and CL3 of the sliding rails 210, 230, and 250 that are arranged parallel to each other are located. The central plane CS is parallel to a plane defined by the X-axis and Y-axis of coordinates.

If all of the longitudinal central lines CL1, CL2, and CL3 of the sliding rails 210, 230, and 250 that are arranged parallel to each other are located on the central plane CS, the sliding device 200 can have a symmetric structure with respect to the central plane CS.

In this case, because the raceways 213, 233, 235, and 253 can form a symmetric structure with respect to the central plane CS, the sliding device 200 that can be installed on one side of the drawer 13 can also be installed on the other side of the drawer 13.

Furthermore, in the sliding device 200 according to the first embodiment of the present invention, each sliding rail 210, 230, 250 has a symmetric structure with respect to the central plane CS including all of the longitudinal central lines CL1, CL2, and CL3. Therefore, symmetrical to the above-explained portion of the sliding device 200, description of the remaining portion of the sliding device 200 that includes the flanges 211′ and 231′ and the balls 220′ and 240′ will be omitted. Also, in the following description of the other embodiments of the present invention, if a part has a symmetric structure with respect to the central plane CS, only one of either side of the part will be representatively explained.

For reference, in the above description of the sliding device 200 according to the first embodiment of the present invention, although a pair of support surfaces has been illustrated as being formed on each raceway 213, 233, 235, 253, the number of support surfaces may be increased so long as the sliding device can have a symmetric structure with respect to the vertical direction VL. An increase in the number of support surfaces increases the number of support points at which the outer circumferential surface of the ball 220 is supported, thus dispersing as much force applied to the ball 220 as possible.

FIG. 6 is a sectional view of a sliding device for a drawer according to a second embodiment of the present invention.

Referring to FIG. 6, the sliding device 300 according to the second embodiment of the present invention includes two sliding rails 310 and 350 and a plurality of balls 320 and 340. Each sliding rail 310, 350 is provided with a pair of flanges 311, 351. For the sake of explanation, the two sliding rails 310 and 350 respectively refer to a first sliding rail 310 and a second sliding rail 350 sequentially arranged.

The balls 320 are disposed between the flange 311 of the first sliding rail 310 and the flange 351 of the second sliding rail 350 that is adjacent to the flange 311.

A raceway 313 in which a portion of a first side of each ball 320 is disposed is formed in a surface of the flange 311 of the first sliding rail 310. A raceway 353 in which a portion of a second side of the ball 320 is disposed is also formed in a surface of the flange 351 of the second sliding rail 350 that faces the ball 320.

The balls 320 are arranged in a line. The raceways 313 and 353 are formed parallel to the retraction direction (B of FIG. 1) or the extension direction (A of FIG. 1) of the drawer (13 of FIG. 1) so that the balls 320 can roll in the direction parallel to the retraction direction B or extension direction A of the drawer 13 under guidance of the raceways 313 and 353. Thereby, the sliding rails 310 and 350 are coupled to each other so as to be slidable in the direction parallel to the retraction direction B or extension direction A of the drawer 13.

FIG. 7 is an enlarged view of portion VII of FIG. 6.

Referring to FIG. 7, a pair of curved support surfaces 3131 and 3133 and a bent part 3135 are formed in the raceway 313 formed in each flange 311 of the first sliding rail 310. For the sake of explanation, the support surfaces 3131 and 3133 respectively refer to a first support surface 3131 and a second support surface 3133. The bent part 3135 is concave in a direction in which the ball 320 is inserted into the raceway 313, so that a portion of the ball 320 can be disposed in the raceway 313. The bent part 3135 is formed parallel to the retraction direction B or the extension direction A of the drawer 13, in other words, parallel to the X-axis of coordinates of FIG. 4. That is, the ball 320, of which a portion of the first side is disposed in the raceway 313, is brought into contact with and supported by the first support surface 3131 and the second support surface 3133.

The first support surface 3131 and the second support surface 3133 are formed to be symmetrical to each other with respect to an imaginary line IC3 connecting the bent part 3135 to a center point O2 of the ball 320. That is, the arc-shaped first support surface 3131 and the arc-shaped second support surface 3133 are symmetrical to each other with respect to the imaginary line IC3.

A pair of curved support surfaces 3531 and 3533 and a bent part 3535 are formed in the raceway 353 formed in a surface of each flange 351 of the second sliding rail 350. The curved support surfaces 3531 and 3533 and the bent part 3535 are symmetrical to the support surfaces 3131 and 3133 and the bent part 3135 with respect to the center point O2 of the ball 320; therefore, further explanation is deemed unnecessary.

For the sake of explanation, the support surfaces 3531 and 3533 respectively refer to a third support surface 3531 and a fourth support surface 3533. The arc-shaped third support surface 3531 and the arc-shaped fourth support surface 3533 are disposed to be symmetrical to each other with respect to an imaginary line IC4 connecting the bent part 3535 to the center point 02 of the ball 320.

A contact point between the ball 320 and the first support surface 3131 refers to a first support point 3132. A contact point between the ball 320 and the second support surface 3133 refers to a second support point 3134. A contact point between the ball 320 and the third support surface 3531 refers to a third support point 3532. A contact point between the ball 320 and the fourth support surface 3533 refers to a fourth support point 3534. In this case, the ball 320 is surrounded by the four support surfaces 3131, 3133, 3531, and 3533, and the outer circumferential surface of the ball 320 is brought into contact with and supported by the four support points 3132, 3133, 3532, and 3534.

The ball 320 is guided by the raceways 313 and 353 surrounding the ball 320 such that the ball 320 rolls in the direction parallel to the retraction direction B or extension direction A of the drawer 13. Therefore, as explained above, even when force is applied to the ball 320 in a direction P1 or P2 inclined to the vertical direction (VL of FIG. 3), the ball 320 can be prevented from being displaced from the original trajectory.

Therefore, in the sliding device 300 according to the second embodiment of the present invention, the sliding rails 310 and 350 can be prevented from being undesirably deformed or worn. The lifetime of the sliding device 300 can also be increased.

For reference, a curvature radius of each of the four support surfaces 3131, 3133, 3531, and 3533 may be changed as needed, for example, when the width of the drawer (13 of FIG. 1) is changed. In detail, the curvature radius of the each support surface 3131, 3133, 3531, 3533 can be determined within a range from more than 50% of a diameter 2Rb of the ball 320 to 60% of the diameter 2Rb.

Meanwhile, a space 3136 is defined between the bent part 3135 formed the raceway 313 of the first sliding rail 310 and the outer circumferential surface of the first side of the ball 320. A space 3536 is defined between the bent part 3535 formed the raceway 353 of the second sliding rail 350 and the outer circumferential surface of the second side of the ball 320. The shape, operation, and effect of the spaces 3136 and 3536 are almost the same as those of the spaces (2136 and 2336 of FIG. 5); therefore, further explanation will be omitted.

In the sliding device 300 according to the second embodiment of the present invention, the four support surfaces 3131, 3133, 3531, and 3533 are oriented perpendicular to the direction of the force (refer to P1 or P2 of FIG. 3) that is applied toward the center point O2 of the ball 320 in a direction inclined to the vertical direction (VL of FIG. 3). Therefore, the four support surfaces 3131, 3133, 3531, and 3533 can most effectively support the force P1 or P2. For reference, the four support surfaces 3131, 3133, 3531, and 3533 are disposed to be symmetrical to each other with respect to the center point O2 of the ball 320. That is, the two imaginary lines IC3 and IC4 described above may be oriented parallel to the vertical direction (VL of FIG. 3).

In the sliding device 300 according to the second embodiment of the present invention, the raceways 311 and 351 may form a symmetric structure with respect to a central plane CS. Thus, the sliding device 300 that is installed on either side of the drawer 13 can be used on the other side of the drawer 13. Therefore, the compatibility of the sliding device 300 as well as parts constituting the sliding device 300 can be enhanced, and inventory can be reduced.

For reference, the first sliding rail 310 is fastened to either the drawer (13 of FIG. 1) or a storage body (11 of FIG. 1) of the storage means (10 of FIG. 1), and the second sliding rail 350 is fastened to the other one of the drawer 13 and the storage body 11. Consequently, the sliding device 300 according to the second embodiment of the present invention can guide the drawer 13 such that the drawer 13 can be smoothly moved relative to the storage body 11 in the retraction direction B or the extension direction A.

Although it is not shown in the drawings, if there is a need for an increase in distance that the drawer 13 can be extended from the storage body 11, at least one additional sliding rail having the same structure as the second sliding rail 230 of FIG. 4 may be installed between the first sliding rail 310 and the second sliding rail 350.

FIG. 8 is a sectional view of a sliding device for a drawer according to a third embodiment of the present invention.

Referring to FIG. 8, the sliding device 400 according to the third embodiment of the present invention includes two sliding rails 410 and 450 and a plurality of balls 420. Each sliding rail 410, 450 is provided with a pair of flanges 411, 451. For the sake of explanation, the two sliding rails 410 and 450 respectively refer to a first sliding rail 410 and a second sliding rail 450 in a sequence of arrangement.

The balls 420 are disposed between the flange 411 of the first sliding rail 410 and the flange 451 of the second sliding rail 450 that is adjacent to the flange 411.

A raceway 413 in which a portion of a first side of each ball 420 is disposed is formed in a surface of the flange 411 of the first sliding rail 410. A raceway 453 in which a portion of a second side of the ball 420 is disposed is also formed in a surface of the flange 451 of the second sliding rail 450 that faces the ball 420.

The raceways 413 and 453 are oriented parallel to the retraction direction (B of FIG. 1) or the extension direction (A of FIG. 1) of the drawer (13 of FIG. 1) so that the balls 420 can roll in the retraction direction B or extension direction A of the drawer 13 under guidance of the raceways 413 and 453.

FIG. 9 is an enlarged view of portion IX of FIG. 8.

Referring to FIG. 9, a pair of planar support surfaces 4131 and 4133, and a bent part 4135 are formed in the raceway 413 formed in each flange 411 of the first sliding rail 410. For the sake of explanation, the support surfaces 4131 and 4133 respectively refer to a first support surface 4131 and a second support surface 4133.

The bent part 4135 is concave in a direction in which the ball 420 is inserted into the raceway 413, so that a portion of the ball 420 can be disposed in the raceway 413. The bent part 4135 is formed parallel to the retraction direction B or the extension direction A of the drawer 13. The ball 420, of which a portion of the first side is disposed in the raceway 413, is brought into contact with and supported by the first support surface 4131 and the second support surface 4133.

Likewise, a pair of planar support surfaces 4531 and 4533, and a bent part 4535 are formed in the raceway 453 formed in a surface of each flange 451 of the second sliding rail 450. The curved support surfaces 4531 and 4533, and the bent part 4535 are symmetrical to the support surfaces 4131 and 4133 and the bent part 4135 with respect to a center point O3 of the ball 420; therefore, further explanation is deemed unnecessary.

Support depressions 4137, 4138, 4537, and 4538, each of which receives therein a portion of the ball 420, are respectively formed in the four surfaces 4131, 4133, 4531, and 4533. The support depressions 4137, 4138, 4537, and 4538 are oriented parallel to the retraction direction B or the extension direction A of the drawer 13. An inner circumferential surface of each support depression 4137, 4138, 4537, 4538 may have an arc-shaped cross-section.

The support surfaces 4131 and 4133 formed on the flange 411 are symmetrical to each other with respect to an imaginary line (not shown) connecting the bent part 4135 to a center point O3 of the ball 420. The support surfaces 4531 and 4533 formed on the flange 451 are symmetrical to each other with respect to an imaginary line (not shown) connecting the bent part 4535 to the center point O3 of the ball 420.

The support depressions 4137, 4138, 4537, and 4538 respectively have concave support portions 4132, 4134, 4532, and 4534, on which the outer circumferential surface of the ball 420 makes contact with the support depressions 4137, 4138, 4537, and 4538. As needed, a curvature radius of the inner circumferential surface of each support depression 4137, 4138, 4537, 4538 may be selected within a range from more than 50% of a diameter 2Rb of the ball 420 to 60% of the diameter 2Rb.

Alternatively, each support surface 4131, 4133, 4531, 4533 may be formed as follows: a curvature center point of the inner circumferential surface of the support depression 4137, 4138, 4537, 4538 coincides with the center point O3 of the ball 420; and a curvature radius of the inner circumferential surface of the support depression 4137, 4138, 4537, 4538 corresponds to a curvature radius of the outer circumferential surface of the ball 420. That is, if the curvature radius of the inner circumferential surface of the support depression 4137, 4138, 4537, 4538 is 50% of the radius 2Rb of the ball 420, the outer circumferential surface of the ball 420 can be brought into line contact with and supported by the inner circumferential surface of the each support portion 4132, 4134, 4532, 4534

In this case, the force with which the raceways 413 and 453 can support the outer circumferential surface of the ball 420 is increased compared to that of the structure in which each raceway comes into point contact with the outer surface of the ball 420. Therefore, if the drawer 13 is designed keeping in mind that a comparatively heavy object may be stored in the drawer 13, it is preferable that the sliding device 400 according to the third embodiment of the present invention be used.

A space 3136 is defined between the bent part 4135 formed the raceway 413 of the first sliding rail 410 and the outer circumferential surface of the first side of the ball 420. A space 4536 is defined between the bent part 4535 formed the raceway 453 of the second sliding rail 450 and the outer circumferential surface of the second side of the ball 420. The shape, operation, and effect of the spaces 4136 and 4536 are almost the same as those of the spaces (2136 and 2336 of FIG. 5); therefore, further explanation will be omitted.

For reference, the support depressions 4137, 4138, 4537, and 4538 of the sliding device 400 according to the third embodiment of the present invention can also be applied to the sliding device 200 according to the first embodiment or the sliding device 300 according to the second embodiment.

Although the preferred embodiments of the sliding device for drawers according to the present invention have been disclosed for illustrative purposes, the spirit of the invention is not limited to the embodiments. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Such modifications, additions and substitutions must be regarded as falling within the scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS

-   -   200, 300, 400: sliding device for drawers     -   210, 230, 250, 310, 350, 410, 450: sliding rail     -   211, 231, 251, 311, 351, 411, 451: flange     -   220, 240, 320, 420: ball     -   213, 233, 235, 253, 313, 353, 413, 453: raceway 

1. A sliding device for guiding a drawer such that the drawer is extended from or refracted into a storage space formed in a storage body, the sliding device comprising: a plurality of sliding rails each having a pair of flanges; and a plurality of balls slidably connecting the sliding rails to each other, wherein each of the flanges comprises a raceway in which a portion of the corresponding ball is disposed, the raceway guiding the ball such that the ball rolls in a direction of extension or retraction of the drawer, wherein the raceway comprises: a bent part extending parallel to the direction of extension or retraction of the drawer, the bent part being concave in a direction in which the ball is inserted into the raceway; and a plurality of support surfaces disposed forming a symmetric structure with respect to an imaginary line connecting a center point of the ball to the bent part, the support surfaces supporting the ball thereon.
 2. The sliding device of claim 1, wherein the support surfaces comprise a pair of support surfaces.
 3. The sliding device of claim 2, wherein each of the pair of support surfaces has a planar shape.
 4. The sliding device of claim 2, wherein each of the pair of support surfaces has a curved shape that is concave toward a portion thereof making contact with the ball.
 5. The sliding device of claim 4, wherein a radius of curvature of the support surface ranges from more than 50% of a diameter of the ball to 60% of the diameter of the ball.
 6. The sliding device of claim 3, wherein each of the pair of support surfaces has therein a support depression in which a portion of the ball is disposed, the support depression extending parallel to the direction of extension or retraction of the drawer.
 7. The sliding device of claim 6, wherein a radius of curvature of the support depression ranges from 50% of a diameter of the ball to 60% of the diameter of the ball.
 8. The sliding device of claim 6, wherein the support depression has a radius of curvature corresponding to a radius of the ball so that the support depression comes into line contact with the ball.
 9. The sliding device of claim 1, wherein a space is defined between the bent part and the corresponding ball.
 10. The sliding device of claim 4, wherein each of the pair of support surfaces has therein a support depression in which a portion of the ball is disposed, the support depression extending parallel to the direction of extension or retraction of the drawer.
 11. The sliding device of claim 5, wherein each of the pair of support surfaces has therein a support depression in which a portion of the ball is disposed, the support depression extending parallel to the direction of extension or retraction of the drawer. 